Solve this Riddle if you can

A kilo consists of 990 grams of water and 10 grams of mushroom material.

After dehydration consists a kilo of 980 grams of water and 20 grams of mushroom material. Hence is the ratio of mushroom material doubled.

This implies that to get the same kilo of mushrooms you would need the double amount of mushrooms material hence the double amount of mushrooms. This implies that the trader needs to give the double number of mushrooms as before, hence will he make $250 loss compared to the week before.

Nop.

You just need to ask yourself how much weight the mushrooms lost.

Alright I'll go ahead and say that 250$ is the correct answer (the mushrooms lost 50% of their weight!). Now all that's left is proving this mathematically using an equation, if anyone's interested.

LoekBergman, the ammount of mushroom cannot increase, only water decreasing.

Ok you reached the right number but this is incorrect. After the dehydration, some water is lost - but the amount of mushroom remains the same! this means that the total weight of the mushrooms is smaller, not the same (therefore he lost some money).

Ya very interesting shoopi  Very strange that 10 pounds would drop to 5 pounds for the 99% water to become 98%, but I found the equation.

We originally had 9.9 pounds water out of 10 pounds total. Let x pounds be lost to dehydration. Now we have 9.9-x pounds water out of 10-x pounds total. And this fraction (9.9-x)/(10-x) must be equal to 98%. Easy to solve, get x = 5 pounds lost to dehydration.

So $250 lost.

He did not assume that the amount of mushroom increased.

 Yes, he assumes it doubles.

He assumed that the amount of mushroom material per kilo(gram) doubled, which was stated in the problem. This is not the same as assuming that mushroom material was created. The total weight of all the mushroom decreases (less kilograms) but the total weight of mushroom material does not, thus the [muskroom material]/[total weight] ratio increases.

This is correct and it's the easiest way to solve it. Good job.

For the first riddle, look at it this way.

Take all the two-child families in the whole world. What proportion of them will have two boys? The answer is 1/4. (Another 1/4 will have two girls. Another 1/4 will have elder boy and younger girl. And the final 1/4 will have elder girl and younger boy.)

Now take all the two-child families in the world, where at least one child is a boy. What proportion of them will have two boys? The answer is 1/3. (Same reasoning as above, but just ignore all the families with two girls.)

If you don't believe me, just interview 100 families you know that have two children, where at least one is a boy. You will find that only about 33 of these families will have two boys. (And not 50.)

He assumed u hv to double the amount of Mushrooms to make up for the weight loss due to the water loss /dehydration ( based on the ratio of % 's given ).. hence the equivalent loss in half the original profit.( half of $500 for 10 pounds=$250 )

Ok,Sorry,u r Right .. it's 1/4 if it doesn't say 1 of them is a boy .( I mixed up that one with the answer to the First Riddle )

but what's the difference between the 1st n' 2nd Riddle,then ?

Both of them states that 1 of them is a Boy n' asks the same Question.

Here's a riddle that does not require math. I'm writing it in my own words though.

A detective is called to a murder scene in a fancy restaurant in town. It is already known that the victim was poisoned by a rare and very strong poison that kills almost instantly. The detective asks around and finds out the victim was having dinner with an acquaintance, who escaped from the scene. The detective examins the victim's table and sees two glasses on it. The one next to the chair of the victim was empty, while the glass next to the chair of his acquaintance had some water in it. He asks what the two men have ordered, and was informed that they both asked for the same beverage and some ice. They were served the beverage from the same bottle. They were not served anything else.

So the question is, how was the victim poisoned?

The acquaintance conspired with the restaurant manager to kill the victim. They put the poison in a bottle of the victim's favorite wine. The glass of water was to help the acquaintance take an antidote before he drank the wine.

Edit: Hmm, I guess the acquaintance escaped with his wine glass. A bit of a stretch. But still possible.

the victim poisoned himself?

The ice was poisoned.

Alright that's a good guess, but, they only had one glass each for the beverage, and neither was served a glass of water (or water).

I suppose he could have found the tap water at the restaurant disgusting and smuggled in a bottle of purified water.

Hmm - nowhere in the stip does it say the acquaintance actually drank any of his beverage. Just that there is some water in the glass. So maybe he discarded the drink to hide the evidence and then replaced it with water from a tap in the restroom.

And we have a winner. The acquaintance conspired with someone on the inside that had access to the ice. The inside man put the poison in the ice and made sure it was served to them. The aquaintance drank his beverage very quickly, while the victim drank his' slowly, so the ice had time to melt so he drank the poison.